A time-domain smart temperature sensor without an explicit bandgap reference in SOI CMOS operating up to 225°C

This paper presents a smart temperature sensor operating over a wide temperature range from 25°C-225°C. The proposed smart temperature sensor eliminates the explicit bandgap reference and only requires the ratio of two diode voltages to obtain ratiometric temperature measurements. The temperature sensor is implemented with a simple time-domain architecture, resulting in low power consumption and small chip area. Fabricated in a PDSOI CMOS process, the proposed smart temperature sensor achieves an accuracy of 2°C over 25°C-225°C and consumes only 25-μA current under a 4.5-V supply with a chip area of 0.45mm².